The present disclosure relates to a display unit displaying an image, and an image processing unit for use in such a display unit, and a display method.
Recently, a cathode ray tube (CRT) display unit has been actively replaced with a liquid crystal display unit or an organic electro-luminescence (EL) display unit. The liquid crystal display unit and the organic electro-luminescence display unit are each being a mainstream display unit due to low power consumption and a flat configuration thereof.
Display units are in general desired to have high image quality. Image quality is determined by various factors including contrast. Increase of peak luminance may be a technique for improving contrast. Specifically, reduction of a black level is limited by reflection of outside light, etc. Hence, in the above technique, peak luminance is increased (extended) to improve contrast. For example, Japanese Unexamined Patent Application Publication No. 2008-158401 (JP-A-2008-158401) discloses a display unit, in which an increasing level (extending level) of peak luminance and gamma characteristics are each varied depending on an average of image signals to achieve improvement in image quality and reduction in power consumption.
In some display units, each pixel is configured of four sub-pixels. For example, Japanese Unexamined Patent Application Publication No. 2010-33009 discloses a display unit, in which each pixel is configured of sub-pixels of red, green, blue, and white to improve luminance or reduce power consumption, for example.